Argument: Natural gas is a fossil fuel that worsens global warming

Issue Report: Natural gas


Matthew Singer. “A case against LNG”. 15 June 2006 – Is LNG, in and of itself, a bad form of energy?

It is dead wrong to think LNG is better than any other fossil fuel. It is not. In fact, it’s worse than domestic natural gas because it’s hotter, meaning that it has a different chemical composition from North American natural gas, which will release more greenhouse gases into the atmosphere. In addition, creating a market for LNG where one is not necessary leads to increased prices, and once LNG has led to increased prices, then different kinds of coal-burning becomes economically equivalent. Far from being a substitute for coal, it will actually create a market for new coal plants.

“Natural Gas Health and Environmental Hazards”. Energy Justice Network – Natural gas is a fossil fuel that is often promoted as “cleaner” than coal, but which has its own serious environmental hazards. Natural gas extraction threatens ecosystems from northern Alaska and Canada to the Gulf of Mexico, including drilling on farms, public lands, forests and parks, in the Rocky Mountains and other coal-field communities, off of U.S. coastal waters and possibly even under the Great Lakes. Pipelines and compressor stations add to the harms, crossing all sorts of ecosystems. Even water bodies like Lake Erie and the Long Island Sound have faced proposals to bury pipelines underwater in trenches that involve stirring up toxic sentiment accumulated on lake/sound floors. Natural gas power plants are significant air pollution sources, releasing hazardous air pollutants, global warming pollution and fine particulate matter.

LNG Watch: “Threat and Impacts” – It contributes to global warming – Natural gas is a fossil fuel that, when burned or released into the atmosphere, contributes to global warming. The process of getting LNG from one continent to another adds greatly to the emissions.

LNG Watch: “LNG and Global Warming” – The LNG industry invariably characterizes LNG as a clean fuel, as if it were identical to domestically produced natural gas that arrives by pipeline. However, the LNG lifecycle adds a significant amount of greenhouse gas emissions above and beyond those produced by domestic natural gas. Significant additional greenhouse gas emissions are generated in the LNG extraction, liquefaction, gasification and transport steps. Depending on the quality of the gas and the distance the LNG must travel, LNG crossing the Pacific may add from 20 to 40 percent more GHG emissions than domestic natural gas. Every segment of the LNG supply chain emits GHGs:

  • The liquefaction plants, which are located in the source region of the LNG, use large amounts of energy to generate power and run compressors that chill the natural gas. This uses between 9 and 10 percent of the natural gas being shipped.
  • LNG carriers are propelled by marine diesel fuel and LNG boil-off gas, emitting substantial amounts of carbon dioxide along their way, which varies by the distance traveled across the ocean; then the mostly empty ship must return to get more, again burning more fuel. This results in another 7 to 12 percent emissions penalty.
  • Production platforms, pipelines, and re-gasification units at the import terminal are all energy-intensive, meaning fuels (mostly natural gas) are converted into carbon dioxide and emitted to the atmosphere.
  • Production platforms and gas processing facilities routinely flare some of the throughput gas.
  • Natural gas is primarily methane and small amounts of heavier hydrocarbon gases including ethane and propane. When these gases are burned they produce carbon dioxide and water vapor. However, some gas deposits also contain significant amounts of naturally-occurring carbon dioxide. Generally this carbon dioxide is simply vented to the atmosphere, contributing to global warming. Most North American natural gas deposits serving California generally have a low carbon dioxide content of two percent or less. In contrast, Pacific Rim gas fields potentially serving as sources for LNG, specifically in Australia and Indonesia, have high carbon dioxide content, ranging from 10 to 15 percent. This inherent carbon dioxide “debit” further aggravates the climate change implications of importing LNG from these source points when it is vented to the atmosphere.

Throughout the process, methane routinely leaks from gas pipelines, storage tanks, compressors, valves, flanges, and seals; methane is also directly vented from the gas processing plant. While routine leaks and vents are not large in terms of mass flow, methane is a greenhouse gas 23 times more powerful than carbon dioxide per unit. According to one study, the range of natural gas loss through these processes is about 1.4 percent. For the “Pacific Connector” pipeline project PG&E has proposed for Oregon, the natural gas will travel 223 miles before it reaches the California border. The farther the gas must travel, the more chances there are for leakages to occur.

Finally, not all of the methane is fully combusted when gas is burned, and these quantities must also be counted. According to a study of BHP Billiton’s Cabrillo Port project, proposed off the coast of Southern California, (which was vetoed by Governor Arnold Schwarzenegger in May, 2007), all aspects of the project combined (liquefaction, transport, consumption of LNG) would have resulted in approximately 25 million tons of GHGs per year, the equivalent emissions of nearly 5 million cars.

Researchers at Carnegie Mellon University found that worst case greenhouse gas emissions from LNG can be as high as those from the best case integrated gasification combined-cycle (IGCC) coal-fired power plants, when both are measured on a lifecycle emissions basis. The strongest environmental argument for LNG is that it might displace coal, which is considered the worst offender among fossil fuels. But multiple studies demonstrate that the greenhouse gas emissions from LNG rivals that of coal under certain circumstances.

“Liquid Natural Gas: A Roadblock to a Clean Energy Future.” Greenpeace. September 2004. – LNG uniquely increases the emissions of CO2 into the atmosphere. The composition of natural gas emissions are identical whether it has been converted to LNG or burned straight from gas. However, the processes necessary to convert and transport LNG are energy intensive. As shown in Table 1, the process of converting natural gas into a liquid, transporting it across the Pacific Ocean, and then returning it to its gaseous form, known collectively as the “LNG supply chain,” requires an increased natural gas consumption of 18-22 percent.1 An additional 11 to 18 percent increase in CO2 emissions is likely to occur because of high CO2 content in the raw source gas being converted to LNG and exported to California or Mexico.2 The CO2 in the source gas may be vented to atmosphere during processing.
The combined impact of venting CO2 during processing and the energy penalty of the LNG supply chain would increase CO2 emissions by roughly 20 to 40 percent over California’s current emissions from domestic sources of natural gas (see Table 1). This increase significantly closes the gap between coal and natural gas with respect to global warming gases.